The Hypatia 308 High Current Sourcing Milliohm Meter provides efficient and accurate stress based testing of safety ground systems to insure that they meet certain performance standards of safety certification agencies such as UL, ETL, TUV, CSA, VDE, BABT and others. It utilizes probes with built in remote sensing or, for multi-point testing or the highest precision measurements, auxiliary Kelvin sense probes. In addition to ground impedance measurements, it can provide and accurately monitor the high currents necessary to test ground system endurance as is required for ground guards on etched circuit boards or in power transformers or other components.
Functionally, the Hypatia 308 Milliohm Meter provides low voltage AC current adjustable to 60 amps rms at the frequency of the power source (typically 60 Hz). This current and the voltage differential at the probe tips it induces are both measured by means of digital signal processing in true rms and divided to yield impedance. The value of the current is displayed continuously on a bar graph, and may be selected to be displayed on the primary digital readout at the same time. Normally, however, the digital readout is selected to display the impedance of the device under test. While the impedance measurement range is 0 to 100 ohms, the center of interest is usually in the 0 to 100 milliohm area. Basic specified accuracy is ± 1% for both impedance and current.